The Preference Size Of Male Mud Crab, Scylla tranquebarica at Success Mating With Female , Scylla olivacea in Controlled Tanks

Abstract

Gunarto, Sulaeman and Herlinah. 2019. The Preference Size Of Male Mud Crab, Scylla tranquebarica at Success Mating With Female , Scylla olivacea in Controlled Tanks. Aquacultura Indonesiana, 20(2) : 93-101. Interspecific hybridization of mud crab Scylla spp has been successfully conducted in controlled tanks. However, there is no information yet available about the male size S. tranquebarica is capable to copulate with female of S. olivacea. The objectives of the experiment is to find out the male size of S. tranquebarica that willingly copulated with newly molted female of S. olivacea. Twelve individual of adolescent female of S. olivacea were reared individually in the conical fibreglass tanks each of 500 L volume. In another tank, 12 adult male S. tranquebarica with various size (200-500g/ind.) were also prepared. The crabs fed with chopped trash fish in the morning (7.00 am) and afternoon (17.00 pm) at 5% of the total crab biomass. Each newly molted female is transfered to the prepared copulation tank where three male of different size have been placed and allow them to mate and freely copulated with the female. The size of copulated crabs (body weight, carapace with, and carapace length) were recorded. The female sizes were measured before and after molting, whereas, the male sizes were measured soon after mating process has finished. Post mating, the female crab then reared individually in the recirculating tank system until mature and spawned. The result showed that male S. tranquebarica with individual weight of >300g are preferable to copulate with female S. olivacea, where in contrary no male crab of the size <300g were successfully mate. The duration from mating to gonad maturity stage IV for the hybridized S. olivacea in this study ranges between 59-103 days.

Interspecific hybridization of decapod crustacean species with commercial interest—A review

“…The hybridization between females of S. olivacea and males of S. tranquebarica could result in a 98% hatching rate, and the duration from zoea 1 to megalopa was observed to be 18 days, 124 which is better to the result obtained by Jantrarotai et al, 133 which was 23.64–24.22 days under varying levels of salinity using larva from the female broodstock of S. olivacea . Furthermore, interspecific hybridization of female S. paramamosain with male S. tranquebarica yielded egg fecundities between 32,200 and 1,868,000 eggs, hatching rates of 2%–45%, and the development of crablets until day 10 after the crablet instar 124 . In addition, based on the author's personal observation, hybridization between S. olivacea and S. tranquebarica (reciprocal) in captivity shows that male S. olivacea × female S. tranquebarica have a higher spawning success rate than the cross between male S. tranquebarica x female S. olivacea .…”

“…The hybridization between females of S. olivacea and males of S. tranquebarica could result in a 98% hatching rate, and the duration from zoea 1 to megalopa was observed to be 18 days, 124 which is better to the result obtained by Jantrarotai et al, 133 which was 23.64-24.22 days under varying levels of salinity using larva from the female broodstock of S. olivacea. Furthermore, interspecific hybridization of female S. paramamosain with male S. tranquebarica yielded egg fecundities between 32,200 and 1,868,000 eggs, hatching rates of 2%-45%, and the development of crablets until day 10 after the crablet instar.…”

“…The mating technology for mud crabs that has been discovered at this time is expected to facilitate mud crab hybridization activities in the future 130,132 . The mating process in mud crabs has been shown to be carried out without going through the precopulation process by pairing newly moulted female crabs with male partners, both during intraspecific breeding 132 or interspecific breeding attempts 124 . The potential use of pheromones, such as uridine diphosphate (UDP) as a female sex pheromone in the European shore crab C. maenas was found to induce courtship behaviour not only in crabs of the same species but also in crabs from different superfamilies and habitats, indicating it is not species‐specific 43 .…”

“…Hybridization in crab to generated offspring in captivity is still rare 130 and to date there is only two genus that has been successfully interbred to produce hybrid offspring in captivity by natural mating. They are namely Eriocheir 131 and Scylla 124,130 . Despite the efforts dispensed in this regards, the progress of hybrid Scylla research is still limited, and the future trends and primary focus of technological development would be to develop a hybrid crab with all of the excellent characteristics performance of the genus Scylla 130 …”

Sexual dimorphism of mud crab, genusScyllabetween sexes based on morphological and physiological characteristics

“…Baiduri et al (2014) worked on hybrid trials between the S. olivacea and S. tranquebarica and observed similar mating activity patterns during precopulatory, copulation and post-copulatory. Also, the success of interspecific hybridization was described through the high egg fecundity (758k) and hatching rate (98%) primarily between the female S. olivacea and male S. tranquebarica (Gunarto et al, 2020b). Previous literature combined the crucial information regarding successfully captivity hybridization besides natural interspecific hybridization within the genus Scylla.…”